1. Field of the Invention
The present invention relates to a retention system for retaining a connector housing of a surface mounted connector to a substrate.
2. Description of the Prior Art
Surface mounted connectors are typically used for interconnecting conductive tracings disposed on one surface of a substrate, such as a circuit board, with corresponding tracings disposed on the surface of another substrate. When using a surface mounted connector some provision must be made for retaining the housing of each connector to the surface of its associated substrate.
One typical retaining expedient includes the provision of a retaining member on one or both ends of the connector housing. The member is extensible into a through-hole provided in the substrate. One example of this expedient is the use of retaining hardware, as a bolt attached to the connector housing, and a cooperating nut which threads to the bolt on the undersurface of the substrate to hold the housing in position.
In other examples of this form of retaining arrangement the retaining member is provided with a hook with a barb which engages the boundary of the through-hole in the substrate. This arrangement is used in the retaining arrangement disclosed in copending application Ser. No. 07/654,854, and copending application Ser. No. 07/654,869, both filed Feb. 13, 1991 and both assigned to the assignee of the present invention. Another example of a barbed retaining arrangement is disclosed in U.S. Pat. No. 4,907,987 (Douty et al.).
In yet another form of such a retaining arrangement the retaining member has a resilient or a compliant feature which permits it to grasp the material forming the boundary of the through-hole. Such an arrangement is shown in U.S. Pat. No. 4,691,971 (Hahn), also assigned to the assignee of the present invention.
Other board retention devices are shown in U.S. Pat. No. 4,025,147 (Van Arsdale et al.), U.S. Pat. No. 4,616,893 (Feldman) and U.S. Pat. No. 5,004,430 (DelGuidice et al.).
When using a surface mounted connector having such a retaining member care must be exercised during manufacture of the substrate that the through-holes therein are accurately positioned with respect to the conductive tracings on the surface of the substrate. To avoid problems attendant upon this registration requirement another retaining expedient utilizes a retainer that is securable, as by soldering, to mounting pads provided on the same surface as the conductive tracings. Since the mounting pads may be placed on the surface of the substrate at the same time as the conductive tracings, the pads may be located to tighter tolerances than the through-holes. An example of such a retaining arrangement is the board-to-board connector system manufactured and sold by Hirose Inc. as the HRS DF9 Series Board to Board Connector.
This last-mentioned retaining arrangement uses a rectanguloid abutment tab formed on at least one endwall of the connector housing. An L-shaped retaining clip having a cut-out formed in one leg thereof is inserted onto the abutment tab from the upper surface of the connector housing. The clip is held to the endwall by a pair of arms. The second leg of the clip is soldered or otherwise attached to the mounting pad, thereby to secure the housing on the surface of the substrate.
During manufacture of this last-mentioned retaining arrangement the retaining clip must be inserted onto the connector housing from the upper surface of the housing, that is, the surface that lies farther from the substrate when the connector is secured thereto. Although the electrical contact elements of this last-discussed retaining arrangement also happen to be inserted into the housing from the upper surface, there are instances where it is necessary or desirable to introduce the electrical contact elements into the housing from the lower surface of the housing, that is, from the surface that lies closer to surface of the substrate. For example, if the electrical contact elements are of the type having a curved transition portion that defines an open and a closed end the location of the carrier strip on such a contact would make insertion from the lower surface of the housing preferred. In such an instance, to have the retaining arrangement inserted from the upper surface of the housing, additional manipulative steps would have to be performed during the manufacture of the connector. This would be economically disadvantageous.
In view of the foregoing it is believed to be of advantage to provide a retention system for a surface mounted connector housing that is retained to mounting pads disposed on the same surface of the substrate as the conductive tracings. Moreover, it is also believed advantageous to provide a retention system in which both the retaining clip and the electrical contacts are introduced onto or into the housing from the housing surface that is proximal to substrate when the housing is secured thereto.